There are many situations where it is necessary to make a strong and reliable connection between two substrates. As well as the more general difficulties connected with splicing, particular difficulties may arise, if for example, the substrates to be joined are not of the same size or if an electrical, as well as a mechanical, connection is to be made. One field where a great number of problems have arisen is in the splicing of coaxial cables.
Many methods have previously been proposed for splicing two coaxial cables. All of the previously proposed methods, however, suffer from one or more disadvantages, for example, an imperfect impedance match (which can result in the signal being distorted or garbled), the need to use complicated or time-consuming steps to make the splice, degradation of electrical contact with time, or high expense. A further disadvantage inherent in most previously proposed splicing methods is that the coupling is mechanically weak. Ideally, the splice will have a tensile strength which is at least as great as that of the cable itself, but this ideal situation is rarely, if ever, achieved in the previously proposed splices.
Albert, U.S. Pat. No. 3,502,788 discloses a connector for coaxial cables having an inner tube through which the center conductors are inserted and connected. The tube may have solder wells for solder connecting the inner conductor. The outer conductors of the coaxial cables are connected via an outer rigid cylinder terminating in a flanged portion which contacts the inner surface of the outer conductor by positioning the spliced cable over the flange so it is interposed between the inner insulation covering the inner conductor, and the outer conductor. Electrical contact is obtained by placing a heat-shrinkable plastic member over a ferrule which is in contact with the outer cable insulation to cause, upon heating, the outer conductor to be compressed inwardly against the flange. Such a configuration suffers from the disadvantage that electrical contact is dependent entirely on the pressure exerted by the heat-shrinkable member due to the non-deformability of the flange. In addition, the flange must be of precise dimension as to be inserted between the outer conductor and the inner insulation.
Cook et al., U.S. Pat. No. 3,253,619 discloses a conductor in which a deformable, metallic braid is interposed between an inner tube and an outer jacket in which the jacket and tube may be heat-deformable and serve as inner and outer insulation for coaxial cables. It has been suggested that such a braid may serve as the electrically conductive shield for coaxial cable and mention is made of its use in caps, splices and closures. Nonetheless, there is no teaching of how the braid is used to interconnect coaxial cable, combination with a non-deformable shell or solder impregnation.
The present invention utilizes a deformable and flexible metallic member, such as a braid, to effect electrical connection between the outer conductors of the coaxial cable. Utilizing such a deformable, metallic connection instead of a rigid metal flange provides several advantages. First, greater variations in cable dimensions can be tolerated. Also, cables of different dimensions can be joined. In addition, upon the shrinking of a heat-recoverable outer tube, electrical contact is assured since the metallic braid will readily deform and contact the outer conductor. An even more reliable connection is obtained by impregnating the braid with solder which will bond the braid to the outer conductor during the heat-shrink operation.